1261517812 has 12 divisors (see below), whose sum is σ = 2267322820. Its totient is φ = 613711296.

The previous prime is 1261517809. The next prime is 1261517821. The reversal of 1261517812 is 2187151621.

It can be written as a sum of positive squares in 2 ways, for example, as 658127716 + 603390096 = 25654^2 + 24564^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4261737 + ... + 4262032.

Almost surely, 2^1261517812 is an apocalyptic number.

It is an amenable number.

1261517812 is a deficient number, since it is larger than the sum of its proper divisors (1005805008).

1261517812 is a wasteful number, since it uses less digits than its factorization.

1261517812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8523810 (or 8523808 counting only the distinct ones).

The product of its digits is 6720, while the sum is 34.

The square root of 1261517812 is about 35517.8520183865. The cubic root of 1261517812 is about 1080.5158178447.

The spelling of 1261517812 in words is "one billion, two hundred sixty-one million, five hundred seventeen thousand, eight hundred twelve".